They confirmed that spell damage that visually crits are affected by Randuin's passive, yet will not be affected by any other critical hit modifiers.
A.k.a. Spell Damage cannot actually do critical hits (they do not use the same parameter, e.g. Critical Damage and Critical Chance, as regular critical strikes), but still gets reduced by something designed to counteract critical hits.
It's absolute bullshit. They go along with bugs and bug abuse cases because it's easier for them to NOT do something than to actually fix the problem.
Riven still has no cast points to speak of, because any decent Riven player bypasses the cast points with bug abuse.
Mordekaiser gets demolished from theme to playstyle because Riot decided that Mordekaiser has no place in their game.
Fizz W's active nerfed again, and the only skill worth maxing is yet again E, making his laning phase extremely one dimensional. Instead of making the active apply a DoT and move the %missingHP damage to it, to nerf the synergy with AS and nerf the uptime on the percentage damage, they nerfed the on-hit damage and killed the skill for every Fizz build.
Rengar can cast Ebola in the air but Kha'zix can't cast Void Spike in mid-air, even when both deals similar damage and contributes exactly to nuking/assassinating.
Kalista gets released in a game with no turn rate.
Tahm Kench gets buffed because not enough players played the champion at release when he's an unfair champion to begin with.
Champion interaction is based completely in champion kits and not items, making champion balance as volatile as ever.
Percentage damage allowed tanks to be the best snowballs in the game for a short while, until almost all of them got nerfed.
Shyvana's W base damage got nerfed because she was clearing too well in the jungle, when the problem was her W doing 20% additional damage to jungle monsters.
Sometimes I don't think Riot is doing a good job when they could have done MUCH better.
Sorry if I think Riot doesn't deliver.